IN-SITU SPECTROELECTROCHEMICAL STUDIES OF THE DECOMPOSITION OF HYDROQUINONES ON PLATINUM-ELECTRODES IN DICHLOROMETHANE SOLUTIONS

The decomposition of hydroquinone and of 2,5-di-tert-butylhydroquinone in dichloromethane solutions has been studied by in situ UV absorptio n and by in situ infrared reflection-absorption spectroelectrochemical methods. The UV absorption spectra showed that benzoquinone and 2,5-d i-tert-butylbenzoquinone are respective products of these decompositio ns. The infrared spectra confirmed that the quinones were the principa l reaction products but also indicated that some water was formed duri ng the decomposition processes. The decomposition rates were found to be dependent on electrode potential with a minimum rate corresponding to a maximum coverage for adsorbed hydrogen, a product of the decompos ition. A new infrared absorption at 1713 cm(-1) has been detected at p ositive potentials in the hydoquinone system and has been ascribed to endwise adsorbed benzoquinone.